Power IT MV Live Tank SF6 Circuit BreakerModel OHB

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ABB - a global leader in powerand automation technologies

ABB (www.abb.com) is a global leader in power andautomation technologies that enable utility and industrycustomers to improve performance while loweringenvironmental impact. The ABB group of companiesoperates in around 100 countries.

ABB’s power technologies division serves electric, gasand water utilities, as well as industrial and commercialcustomers, with a wide range of products, services andsolutions for power transmission and distribution. ABBoffers turnkey solutions for substations, utilityautomation, HVDC and FACTS (Flexible ACTransmission System).

ABB’s power technologies product portfolio includesoutdoor and indoor circuit breakers, gas insulatedswitchgear, power transformers, instrumenttransformers, disconnectors, capacitor banks andreactive power compensators.

ABB’s medium voltage product offering encompasses acomplete range of innovative products, systems andtechnologies for applications in the 1 to 50 kV class.This includes indoor air insulated and gas insulatedpanels with vacuum and SF6 gas circuit breakers,outdoor vacuum and SF6 gas circuit breakers, ring mainunits, auto-reclosers, fuses, switch disconnectors andprefabricated modular solutions for power distribution.

Industrial IT

The OHB circuitbreaker is certified ascomplying with theABB IndustrialIT

architecture. In thisarchitecture the OHBcircuit breaker is part of the PowerIT suite. Theproducts complying with the IndustrialIT architecturecan be effectively integrated in a system with highadded value and a true ‘Plug & Produce’ mode.

This product has been tested and certified asIndustrialIT Enabled, Level 0 - Information. Allproduct information is supplied in interactiveelectronic format, compatible with ABB AspectObjectTM technology. The IndustrialIT commitmentfrom ABB ensures that every enterprise buildingblock is equipped with the integral tools necessaryto install, operate, and maintain efficientlythroughout the product lifecycle.

Further information about the advantages ofABB IndustrialIT architecture is available at thefollowing site: www.abb.com/industrialit.

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1 Description .................................................................................. 4

2 Circuit-Breaker Selection and Ordering ...................................... 8

3 Product Characteristics .............................................................. 12

4 Overall Dimensions..................................................................... 14

5 Electric Circuit Diagram .............................................................. 16

Contents

General information

OHB medium voltage circuit-breakers for outdoorinstallation use sulphur hexafluoride gas (SF6) toextinguish the electric arc and as the insulating medium.

Breaking in SF6 gas takes place without currentchopping or generation of overvoltages.

These characteristics guarantee a long electrical life forthe circuit-breaker and limited dynamic, di-electric andthermal stresses on the installation.

The ESH type of stored energy and free releasemechanical operating mechanism allows opening andclosing operations through local and remote control.

The operating mechanism, the activating kinematics ofthe moving contacts and the anti-condensation heaterare located inside a tight metal enclosure which alsoacts as the support for the poles.

The above-mentioned structure is supported by a framemade of telescopic metal sections which allow theheight of the circuit-breaker terminal to be adaptedfrom 2800 mm to 3700 mm.

The metal enclosure has IP 54(*) degree of protectionand is fitted with a tight door with an inspection window.

The circuit-breaker is compact and ensures a high levelof sturdiness and excellent mechanical reliability.

The enclosure is made out of a steel plate withadequate surface protection by a special metalising andpainting process. The support structures are hot dipgalvanised.

Fields of application

OHB circuit-breakers are used in power distribution forcontrol and protection of lines and for control andprotection of transformers, rectifier units, capacitorbanks, etc.

Due to the SF6 autopuffer breaking technique, the OHBcircuit-breakers do not generate overvoltage duringswitching, and are therefore also highly suitable forretrofitting, upgrading and enlarging older installationswhere the insulating materials of the cables andapparatus may have already been stressed duringservice.

� Breaking chamber identical to the type usedfor the HD4 series

� Mechanical operating mechanism identicalto the type used for the HD4 series

� Upper and lower terminals with NEMA4drilling

� Gas pressure control device for each pole

� Poles made with porcelain insulators,assembled by means of flanges withterminals

� Pole covers and cases made of aluminium

� Pole covers with safety valve

� Inspection window in the pole supportingcasing near the operating mechanismsignals

� Complete range of accessories

� Wide range of power supply voltages of theelectrical accessories

Description

(*) IP 54 is obtained by placing filters over theventilation holes on the bottom of the casing(the filters are supplied on request)

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Standards and approvals

The OHB circuit-breakers comply with the IEC 62271-100 standard as well as of other major industrialisedcountries. They have undergone the tests indicatedbelow and ensure service safety and reliability of theapparatus in all installations.

Type tests:

� Temperature rise test

� Di-electric test

� Short circuit test duties

� Short time current test

� Mechanical endurance test

Routine tests:

� Power frequency voltage with stand test

� Insulation test on auxiliary and control circuits

� Measurement of main circuit resistance

� Mechanical and electrical operation test

Service safety

The mechanical and electrical locking devices havebeen provided to prevent incorrect operations and tocarry out inspection of the installations whileguaranteeing maximum operator safety.

Porcelain insulators

Telescopic supportsLower terminals

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Accessories

The OHB circuit-breakers have a complete range ofaccessories which means all installation requirementscan be satisfied.

The operating mechanism is of the same type for thewhole series and has a standardised range ofaccessories and spare parts which are easy to identifyand order. Use, maintenance and service of theapparatus have been simplified and require limited useof resources.

ESH operating mechanism

� Single operating mechanism for the whole series

� The same accessories for all types of circuit-breakers

� Easy assembly and replacement of the accessories

Device for monitoring SF6 gas pressure

ESH type of operating mechanism

Detail of the supports for fixing to the floor

Quality Assurance SystemCertified by an independent organisation as complying with ISO 9001 Standards.

Environmental Management SystemCertified by an independent organisation as complying with ISO 14001 Standards.

Test laboratoryAccredited by an independent organisation as complying with ISO 45001 Standards.

Circuit-breaker OHB 24 OHB 36 OHB 40

Rated voltage [kV] 24 24 36 36 40.5 40.5

Rated normal current [A] 1250 2500 1250 2500 1250 2500

Rated breaking capacity [kA] 25-31.5 25-31.5 25-31.5 25-31.5 25-31.5 25-31.5

Electrical characteristics

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Breaking technique

The breaking principle of OHB circuit-breakers is based on compression and self-blast technique to obtain topperformances at all breaking current values, with minimum arc times, gradual arc extinction without chopping, andno restriking or switching overvoltages.

This breaking technique - already widely appreciated and used in high voltage circuit-breakers, has beenintroduced into medium voltage with the HD4 series circuit-breakers for indoor installation.

Main contact separationNo electric arc is struck because the current flows through the arcingcontacts. During its run downwards, the moving apparatus compresses thegas in the lower chamber. The compressed gas flows from the lower to theupper chamber, thereby taking both the chambers to the same pressure.

Arcing contact separationThe current flows due to the electric arc which has struck between thearcing contacts. The gas cannot escape through the nozzle because thehole is still closed by the fixed arcing contact and cannot even escapethrough the inside of the arcing contact, because of the clogging effect ofthe electric arc.

• at low current values, the arc is extinguished when the current passesthrough its natural zero and the gas flows through the contacts. The lowpressure level cannot chop the current and the modest amount of gaswhich “escapes” is sufficient to restore di-electric resistance betweenthe two contacts, preventing restriking on the rising front of the recoveryvoltage.

• at high short-circuit values, the pressure wave generated by theelectric arc closes the valve between the two chambers so that thecircuit-breaker starts to operate as “pure self-blast” apparatus. Thepressure increases in the upper volume due to the gas heating andmolecular dissociation due to the high temperature. The pressureincrease is proportional to the arc current and ensures arc extinctionduring the first passage through zero current.

Circuit-breaker openThe arc has been extinguished, the self-generated pressure in the uppervolume decreases because the gas is flowing through the contacts. Thevalve re-opens and a new jet of fresh gas flows in and “washes” thechamber. This means the apparatus is immediately ready to close and tripagain up to its maximum breaking capacity.

Circuit-breakerclosed

Main contactseparation

Arcing contactseparation

Circuit-breakeropen

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2

9

7

3

6

45

1

2

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1 Terminal

2 Insulating enclosure

3 Blasting nozzle

4 Moving arcing contact

5 Moving contact

6 Fixed arcing contact

7 Fixed contact

8 Insulating tie-rod

9 Cap with bursting valve

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General characteristics

Circuit-Breaker Selection and Ordering

Circuit-breaker on column OHB 24 OHB 36 OHB 40

Standards IEC 62271-100 � � �

Rated voltage Ur [kV] 24 36 40.5

Rated insulation voltage Us [kV] 24 36 40.5Withstand voltage at 50 Hz Ud (1 min) [kV] 70 (dry) / 60 (wet) 95 (dry) / 80 (wet) 95 (dry) / 80 (wet)Impulse withstand voltage Up [kV] 150 200 200

Rated frequency fr [Hz] 50-60 50-60 50-60

Rated normal current (400C) lr [A] 1250 2500 1250 2500 1250 2500

Rated breaking capacity Isc [kA] 25 25 25 25 25 2531.5 31.5 31.5 31.5 31.5 31.5

Rated short-time Ik [kA] 25 25 25 25 25 25withstand current (3 s) 31.5 31.5 31.5 31.5 31.5 31.5

Making capacity Ip [kA] 63 63 63 63 63 6380 80 80 80 80 80

Operation sequence [O-0, 3s-CO-15s-CO] � � �

Opening time [ms] 45+10 45+10 45+10Arcing time [ms] 10-15 10-15 10-15

Total breaking time [ms] 55-60 55-60 55-60Closing time [ms] 75+10 75+10 75+10

Overall dimensions on frameH [mm] 3090 – 3840 3090 – 3840 3090 – 3840L [mm] 900 900 900

P [mm] 686 686 686

Weight [Kg] 900 900 900

SF6 gas absolute pressure Rated service value [kPa] 380 380 550Operating temperature (1) [0C] –25...+40 –25...+40 –25...+40Tropicalisation IEC: 60068-2-30, 721-2-1 � � �

Electromagnetic compatibility IEC: 60694, 61000-6-2, 61000-6-4 � � �

Solar radiation [W/m2] 1000 1000 1000

Presence of pollution IEC 815 - table 1 Level III Level III Level IIICreepage distance [cm/kV] 2.5 2.5 2.75Ice coating [mm] 10 10 10

Wind speed [m/s] 34 34 34Earthquake resistance [g] 0.3 0.3 0.3

Static force on the terminals Longitudinal [N] 750 750 750Transversal [N] 500 500 500

Vertical [N] 750 750 750

(1) For lower operating temperatures, please consult us.

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Identification of the circuit-breaker type

The identification code of a circuit-breaker is made upwith the elements indicated in the table below. Forcorrect identification of a circuit-breaker, please refer tothe characteristics table on page 8. The circuit-breakerselected can then be completed with the optionalaccessories indicated on the following pages.

Example of identification: code OHB 36.25.32identifies a circuit-breaker for outdoor installation with36 kV rated voltage, 2500 A rated normal current and31.5 kA breaking capacity.

Standard equipment

1) ESH operating mechanism, complete with manualopening and closing push buttons, mechanical keylock in open position (key removed in the openposition), mechanical indicators for circuit-breaker“open or closed” and for springs “charged ordischarged”, the mechanical indicators can beseen through the inspection window on the door

2) YO1 shunt opening release

3) YC shunt closing release

4) Spring-charging geared motor

5) Lever for manual spring charging

6) Pressure switch with two levels (one per pole);suitable for operation down to -250C. For lowerservice temperatures, please contact us

7) Locking circuit for insufficient gas pressure(automatic opening with additional YO2 shuntopening release and lock in the open position bymeans of closing circuit interruption)

8) Electrical contacts signalling:springs charged (or alternatively springsdischarged)

9) Auxiliary contacts (10 NC + 10 NO)

10) Automatic remote operation is not possible with thedoor open by means of a limit switch mounted onthe door

11) Anti-condensation/heating circuit for lowtemperatures with armoured anti-condensationheating elements and thermostat; solution providedfor operation down to -250C

12) Support terminal box with isolation for YO1 shuntopening release, YC shunt closing release, Mmotor and YU undervoltage release (if requested)

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Shunt closing release

13) The cabinet is fitted with cable gland plate forcontrol, cables and with padlockable front door

The circuit-breaker is supplied with asymmetricalterminal connections on one side of the poles onlyand with 4 holes as per NEMA form 4 Standards.The lower terminal is turned towards the rear of theapparatus, the upper terminals are provided asstandard turned towards the front of the apparatusbut, on request, it can be turned towards the rear ofthe apparatus

The structures provided are:

� T structures with telescopic supports adjustable inheight

� The structure and framework are always made ofhot galvanised steel

Equipment supplied on request

14) MCB for geared motor protection

15) Signalling lamps placed inside the cabinet, in aposition visible from the inspection window on thedoor. A single solution with 4 lamps is provided for:

� signalling circuit-breaker closed (red lamp)

� signalling circuit-breaker open (green lamp)

� signalling springs charged (or alternativelydischarged) (yellow lamp)

� signalling insufficient gas pressure (white lamp)

16) Selector switch for local/remote control

17) Control switch for local ON/OFF electricaloperation through shunt closing and openingreleases

18) YU undervoltage release

19) Electrical signalling of YU undervoltage releaseenergised (or de-energised)

20) Electronic time delay device for YU undervoltagerelease

21) Q0 Transient closing contact (NO contact whichcloses transiently during circuit-breaker opening)

22) 20 auxiliary switches contacts (10 NO + 10 NC)

23) Single-phase socket

24) Illumination lamp which automatically switches onby means of a limit switch when the door is opened

25) IP54 ventilation filters on the discharge holeslocated on the bottom of the casing

26) CT support structure units terminal connector

Shunt opening release Undervoltage release Auxiliary contacts with linkage

Spring charging geared motor

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Characteristics of the electrical accessories of the ESH operating mechanism

Shunt opening release Ps = 125 W / VA x 45 ms (instantaneous service)Un = 24, 30, 48, 60, 110, 125, 220 V–Un = 48, 110, 127, 220, 230, 240 V~ 50 HzUn = 110, 127, 220, 230, 240 V~ 60 Hz

Shunt closing release Ps = 250 W / VA x 150 msPc = 5 W / VA (anti-pumping function - continuous service)Un = 24, 30, 48, 60, 110, 125, 220 V–Un = 48, 110, 127, 220, 230, 240 V~ 50 HzUn = 110, 127, 220, 230, 240 V~ 60 Hz

Undervoltage release Ps = 250 W / VA x 150 msPc = 5 W / VA (continuous service)Un = 24, 30, 48, 60, 110, 125, 220 V–Un = 48, 110, 127, 220, 230, 240 V~ 50 HzUn = 110, 127, 220, 230, 240 V~ 60 Hz

Spring charging geared motor Ps = 1500 W / VA x 100 msPc = 400 W / VA x 6 sUn = 24, 30, 48, 60, 110, 125, 220 V–Un = 48, 110, 127, 220, 230, 240 V~ 50 HzUn = 110, 127, 220, 230, 240 V~ 60 Hz

Signalling contacts Un = 110 V~ 230 V~ 400 V~ 110 V– 220 V–Icu = 4 A 3 A 1.5 A 0.25 A 0.13 Acosϕ = 0.3 0.3 0.3 – –T = – – – 10 ms 10 ms

Signalling contacts Un = 400 V~ 220 V–Icu = 15 A 1.5 Acosϕ = 0.4 –T = – 10 ms

Un Rated voltage

Cosϕ Power factor

Icu Breaking capacity

Ps Inrush absorbed power

Pc Continuous service absorbed power

T Time constant

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Resistance to vibrations

The OHB circuit-breakers are unaffected by mechanicalvibrations.

Tropicalisation

The OHB circuit-breakers aremanufactured in compliancewith the strictest regulationsfor use in hot-humid-salineclimates.

All the important metalcomponents are treatedagainst corrosion. The sheetmetal components are

metalised with zinc and painted to ensure protectionagainst corrosion. The support structures are hot dipgalvanised. These construction characteristics meanthe OHB circuit-breakers and their accessories complywith climate graph 8 of the IEC 60721-2-1 and IEC60068-2-2 (Test B: Dry Heat) / IEC 60068-2-30 (TestBd: Damp Heat, cyclic) Standards.

Altitude

The insulating property of airdecreases as the altitudeincreases. This fact musttherefore be taken into accountfor external insulation of theapparatus (the internal insula-tion does not undergo anyvariation because it is guaran-teed by the SF6 gas).

The phenomenon must always be considered duringthe design stage of the insulating components of theapparatus which are to be installed over 1000 m abovesea level.

In this case a correction coefficient must be consid-ered, which can be taken from the graph at the side,built up on the basis of the indications in the IEC 60694Standards.The following example is a clear interpretation of theindications given above.

Example

� Installation altitude: 2000 m

� Service at 24 kV rated voltage

� Power frequency withstand voltage: 70 kVrms

� Impulse withstand voltage: 150 kVp

� Ka factor, which can be taken from the graph = 1.13

Considering the above parameters, the apparatus mustwithstand (on test at zero altitude, i.e. at sea level).

– power frequency withstand voltages:

70 x 1.13 = 79.1 kVrms

– impulse withstand voltage:

150 x 1.13 = 169.5 kVp

From the above, it can be deduced that for installationsat an altitude of 2000 m above sea level, with 24 kVservice voltage, apparatus must be provided with 36 kVrated voltage, characterised by insulation levels atpower frequency of 95 kVrms with 200 kVp impulsewithstand voltage.

Product Characteristics

Graph for determining the Ka correction factoraccording to the altitude

H = altitude in metres

m = value based on power frequency, impulse andphase to phase withstand voltage

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Operation of special loads

The table shows the breaking capacities which can be guaranteed for operation of special loads.

N.B. The maximum overvoltages found in all breaking, under the conditions considered, are < 2.5 PU

(*) Back-to-back: 400 A, 20 kA inrush current, 4.25 kHz inrush frequency; for higher values of capacitivecurrents, please consult us.

Environmental protection programme

The OHB circuit-breakers are manufactured inaccordance with the ISO 14000 Standards (Guidelinesfor environmental management).

The production processes are carried out in compliancewith the Standards for environmental protection interms of reduction in energy consumption as well as inraw materials and production of waste materials. All thisis due to the medium voltage apparatus manufacturingfacility environmental management system, certified byan external independent organisation.

Assessment of the environment impact during the lifecycle of the product (LCA - Life Cycle Assessment), iscarried out during the design stage itself and materials,processes and packing methods are selected tominimise the same.

Production techniques which prepare the products forsimple dismantling and separation of the componentsare used during manufacture of the circuit-breakers.This is to allow maximum recycling at the end of theuseful life cycle of the apparatus.

Anti-pumping device

The ESH operating mechanism on OHB circuit-breakers (in all versions) is fitted with a mechanicalanti-pumping device which prevents reclosing due toeither electrical or mechanical commands.

Should both the closing command and any one of theopening commands be active at the same time, therewould be a continuous succession of opening andclosing operations. The anti-pumping device avoids thissituation, ensuring that each closing operation is onlyfollowed by a single opening operation and that there isno closing operation after this. To obtain a furtherclosing operation, the closing command must bereleased and then relaunched.

Circuit-breaker OHB

Rated normal current In [A] 1250 2500

No-load MV/LV transformer breaking Isc [A] 10 10

No-load line breaking Isc [A] 31.5 31.5

Capacitive current breaking (single bank) Isc [A] 400 (*) 400 (*)

Compensation reactance current breaking Isc [A] 630 1250

Furthermore, the anti-pumpingdevice only allows circuit-breaker closure if the followingconditions are present at thesame time:

– operating mechanismsprings fully charged

– opening push button and/oropening release (YO1) not enabled

Spare parts– Opening springs (1)– Closing springs (1)– Complete pole (1)– Basic operating mechanism (1)– Spring charging geared motor (1)– Geared motor limit contact– Anti-condensation heater– Shunt opening release– Thermostat– Operating mechanism auxiliary contacts (1)– Undervoltage release (1)– SF6 gas filling kit (2)– SF6 5-litre gas cylinder (2)

Ordering

For availability and ordering of spare parts, pleasecontact the ABB Service, specifying the circuit-breakerserial number.

(1) Replacement can only be carried out by trained personnel and/or in our workshops.

(2) Only to be used by trained personnel or at an ABB Service.

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Overall Dimensions

OHB36 OHB40

Ur 36 kV 40.5 kV

Ir 1250 A 1250 A2500 A 2500 A

Isc 25 kA 25 kA31.5 kA 31.5 kA

Front View Front View

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Side View w/o CT Structure Side View with CT Structure (optional)

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Electric Circuit Diagram

Legend Description

OHB Circuit Breaker

Closing Coil (CC) YCTrip Coil (TC1) Y01Trip Coil (TC2) Y02

Spring Charge Motor

MCB

Indicating Lamp

Breaker Aux. Contacts

Anti-Pumping RelayGas Pr. Low Alarm RelayGas Pr. Low Trip Relay

Breaker Control Switch

Local Remote Switch

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Control circuit

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Auxiliary circuit and indication

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Accessories and motor circuit

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1VD

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YN03

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